Easy "Nailed it" achievement
Hit the button halfway through bonus level 2, "Hammer" before it disappears. To do this, rush through as fast as possible. The switch is about the halfway point with 3x3x3 cubes, with a hole in the middle. One of those cubes has a button that eventually disappears. Hit that button. Falling off the level forces the switch to rise to where it was in the checkpoint.
Easy "Minimalist" achievement
Go through the level as usual. When you reach the nine switches, press the one at the middle-left. Then, quickly climb on the block that appears on your left. If you fail, fall off the level and try again.
Easy "Backpack" achievement
Start level 18 "Edge Time", and progress until the final button. Just after pushing it, fall down that block and edge it eight seconds. It should appear as if you are the human's backpack.